The present invention relates to a sequential numbering machine for injection moulds, the evident purpose of which is that of marking pieces which are obtained by injection moulding, so that the numbering machine acts in accordance with each electromechanical impulse which it receives in each injection cycle, or what is the same thing, in each injection moulded piece.
It is an object of the invention to provide the plastics injection sector with a sequential numbering machine in order to be able to mark the pieces which are being obtained by injection, the operation being carried out automatically without the numbering machine being subjected to filtrations of plastic during the injection process, avoiding thereby possible jamming and malfunctioning.
Numerous types of numbering machines are known for carrying out marking of different kinds, from marking with letters, to numbers, signs, logotypes, etc., so that the change from numbers or symbols is carried out manually by means of turning a lever which will give rise to the turning of the wheel bearing the numbers, to obtain the figure that is wanted.
Nevertheless, although numerous types and forms of numbering machine exist for the marking of different pieces, objects and articles, no numbering machine is known in the plastic injection sector, which is simply due to the difficulty involved basically in achieving a level of total sealing, so that the plastic is not introduced in the injection process through the multiple moving pieces and spaces existing in the numbering machines marketed at the moment.
The numbering machine proposed, is foreseen precisely to resolve the problem explained above, being based on the adequate arrangement and operation of the cams and wheels which combine to form the numbering machine, all this enclosed in a cylindrical casing from which emerges a spindle finished in a plunger which is operated by electromechanical impulses, which spindle being associated with a spring which tends to constantly push it outward in order that the electromechanical impulse presses toward the interior and acts on a transversal lever mounted so that it can rotate about the spindle""s end, which end being housed inside the cylindrical casing like the lever, which has on each of its ends an arm mounted also so that it can rotate but pushed constantly, in one case toward the cams of the numbering machine and in the other case toward the wheels of the numbering machine itself.
The cams and the wheels are connected in pairs, so that the sectorial turning of a cam signifies the turning of the wheel associated therewith, the turning of each cam and therefore of each wheel being independent, with the particularity that an axle exists on one of whose halves is mounted the wheel assembly and on the other half the cam assembly, the outermost cam of one side and the outermost wheel of the opposite one being connected on the axle itself, so that the turning of that cam signifies the turning of the wheel. Likewise, the cam adjacent and more internal to that previously referred to is connected with the wheel adjacent to that of the other end, so that the turning of that second or more internal cam, signifies the turning of the second wheel and so forth, so that each wheel and cam are connected to each other by means of a cylindrical shell, the different cylindrical shells which constitute the means of linking between wheels and cams being concentric.
One of the arms articulated on the corresponding end of the lever previously referred to, is finished in a toothed heel, with the teeth arranged in a stepped manner, including as many teeth as the number of cams and wheels comprising the counter, which will correspond specifically with the number of figures it is desired to number, so that if the figure it is desired to mark on a piece is six, it will incorporate six cams, six wheels and, the arm or toothed heel of the latter, six teeth.
As mentioned, that arm is pressed by means of a spring or band toward a position of pushing against the cams.
Each of the cams has nine peripheral recesses, which correspond to the first nine numbers, and an inlet, so that the recesses are defined by corresponding projections against which will press one of the teeth of the toothed heel, all this so that every time the plunger receives an electromechanical impulse, the axial displacement which the spindle associated with that external plunger undergoes, signifies the rocking of the lever and corresponding thrust of the arm bearing the toothed heel, and with this the partial turning of the cam, the angular segment of turning being that which is defined between each pair of consecutive projections, so that the turning of the cam in question will signify the turning of the corresponding wheel, the rest remaining immobilised as a consequence of a positional lock with which, for this purpose, the arm foreseen on the opposed end of the other lever is fitted, that positional latch being also pressed by a spring or band toward a position of pushing against the numbered wheels, and equipped with as many prongs as wheels, so that each prong presses on a wheel and maintains it immobilised during the turning of the cam which is operated by the toothed sector of the other arm, the thrust from this arm being greater than the thrust on the positional lock in order to allow the turning of each cam and, however, to maintain the remaining numbered wheels immobilised.
Each sector through which the cam rotates, will correspond to the advance of a number of the corresponding wheel, and therefore in each cycle a figure will be stamped, and in the following cycle the figure immediately higher, and so forth, until when the cam has turned through the nine sectors comprised between the different projections, the toothed sector reaches the hollow of said cam, in which all said toothed sector of the arm is positioned, so that in the following cycle and corresponding rocking of the lever, the engagement commences of the next tooth of the toothed sector on the second cam, which will signify the turning of the latter and with it that of the second wheel, until conclusion of the numbering of this second wheel and so forth, continuing with the third, etc.
The cylindrical casing from which only the spindle emerges with the spring guided in a sheath, and which spindle is finished in the corresponding plunger, presents the particularity that in the opposite end or upper part of said body or cylindrical casing, an opening has been foreseen coincident with the numbers, symbols or figures foreseen on the wheels, which permits the marking of each injected plastic piece.
The numbered wheels foreseen on the ends of the assembly are wider than the intermediate ones to avoid possible filtrations of plastic through those sides, whereby the necessary sealing is achieved for this application, also at that point.
The sequential numbering machine also allows diverse alternatives, since the numbers can be located on the numbered wheel in a planar or concave manner.
Finally, it is mentioned that in a variant or alternative embodiment, the numbering machine can incorporate a second counter which would allow multiplying by xe2x80x9cXxe2x80x9d, the numbering capacity of the numbering machine itself, so that said second counter is moved manually and would be mounted in a space foreseen for this purpose in the upper part of the general cylindrical casing of the numbering machine, with the disposition of some O-rings which avoid or brake the position and do not rotate in free motion.